There’s no question that Roundup Ready (RR) crops have made many no-till weed management decisions simpler on millions of acres of soybeans, cotton and corn.
The efficacy of over-the-top applications of glyphosate herbicides such as Touchdown with IQ Technology (diammonium glyphosate) from Syngenta and Monsanto’s Roundup Ultra and Roundup Ultra MAX (the IPA salt of glyphosate) have provided outstanding control of emerged weeds in RR crops.
Bob Klein, extension cropping systems specialist at the University of Nebraska’s experiment station in North Platte, Neb., points out that both Touchdown and Roundup provide equally excellent weed control. But any herbicide needs to be applied properly to get the product absorbed into target weeds, deliver great results and avoid drift.
Klein offers growers a few tips as the no-till post-emergence spraying season approaches.
“A 3-to-10-mile-per-hour wind away from susceptible vegetation is ideal,” says Klein. “The worst time to spray in is dead calm conditions.”
He points out that light winds (0-3 mph) tend to be unpredictable and variable in direction and may signal a temperature inversion. In inversion conditions, where the temperature increases as you move upward, spray droplets tend to become suspended in the air and drift aimlessly.
Klein says a University of Nebraska study conducted on glyphosate sprayed at various times of day and night showed that when the herbicide is applied can have a significant effect on its effectiveness on tough weeds. When weed metabolism slows down for the night, he says…